1. Field of the Invention
The present invention relates to an embedded substrate and a method for making the same, and more particularly to an embedded substrate having a circuit layer element with an oblique side surface and a method for making the same.
2. Description of the Related Art
FIGS. 1 and 2 respectively show a cross-sectional view and a partial enlarged view of a conventional embedded substrate having a circuit layer element. The conventional embedded substrate 1 having the circuit layer element comprises a core layer 11, a first copper layer 12, a dielectric layer 13 and at least one circuit layer element. The first copper layer 12 is disposed on the core layer 11. The dielectric layer 13 is disposed on the first copper layer 12. The dielectric layer 13 has an upper surface 131 and an accommodating groove 132, 133, 134, and the accommodating groove 132, 133, 134 opens at the upper surface 131. The circuit layer element (for example, a conductive trace 14, a pad 15 or a through via 16) is disposed in the accommodating groove 132, 133, 134 of the dielectric layer 13.
The conventional embedded substrate 1 having a circuit layer element has the following disadvantages. The circuit layer element (for example, the conductive trace 14) has a sharp edge at a border with the dielectric layer 13. Because electrons 17 have the characteristic of easily gathering at the sharp edge during electrically conducting, the gathered electrons 17 induce more heat and more resistance at the sharp edge. Therefore, the signal strength will be lessened when transmitting.
Moreover, conventionally, an orientating land 18 must be formed before forming a through via 16, so that the accommodating groove 134 is then formed after confirming the position of the through via 16, which increase the contact area and the combining strength between the through via 16 and a solder (not shown). However, in order to form the orientating land 18, layout design must be well-considered, thus cause inconvenience.
Therefore, it is necessary to provide an embedded substrate having a circuit layer element with an oblique side surface and a method for making the same to solve the above problems.